import javax.swing.tree.TreeNode;

    class TreeNode {
      int val;
      TreeNode left;
      TreeNode right;
      TreeNode() {}
      TreeNode(int val) { this.val = val; }
      TreeNode(int val, TreeNode left, TreeNode right) {
          this.val = val;
          this.left = left;
          this.right = right;
      }
  }
   public class Solution {
    public boolean isSameTree(TreeNode p, TreeNode q) {
        if (p == null && q == null){
            return true;
        }
        if(p != null && q ==null || p == null && q!= null){
            return false;
        }
        if (p.val != q.val){
            return false;
        }
        return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
    }
}
